Remove the fields in kmem_cache_cpu that were used to cache data fromkmem_cache when they were in different cachelines. The cacheline that holdsthe per cpu array pointer now also holds these values. We can cut down thekmem_cache_cpu size to almost half.

The get_freepointer() and set_freepointer() functions that used to be onlyintended for the slow path now are also useful for the hot path since accessto the field does not require an additional cacheline anymore. This resultsin consistent use of setting the freepointer for objects throughout SLUB.